Two thousand five hundred and seventy four kilometres
long; flowing past six countries, through 2 hydroelectric dams, under seven
bridges and over the magnificent Victoria Falls, the Zambezi River (’the Great
River’ in Tsonga) is the longest river flowing east and the fourth longest river in Africa, its catchment area (1 390
000km2) is half the size of Europe.
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| View of the gorge downriver from the dam wall |
The second hydro-electric dam to be built on the Zambezi is at Mozambique’s Cahora Bassa gorge, 125 kilometres away from Tete, the provincial capital. Even on the sunniest day, the gorge has an imposing manner; the chasm bursts with menace. Enormous rocks and boulders are chaotically piled and scattered as if some almighty infant deity, tired of his building blocks, swept them aside in a childish tantrum. Millions of tons of water, forced into the narrow crevice created by the frowning and formidable ravine walls, crash and swirl down the impassable rapids.
Where the Work Ends
The local Tsonga named the rapids
‘Kebrabasa – where the work ends’, a faultless description of the impossibility
of passage beyond that point. And
Kebrabasa was responsible for the failure of David Livingstone’s 1858 Zambezi
expedition - the obstinate doctor finally conceding defeat when his paddle
steamer, MaRobert, simply could not
get more than three kilometres beyond the gorge entrance. “God’s Highway”, as Livingstone
had described the Zambezi to his financial backers in England, was not to
be. The river defied all attempts to
exploit it as access to the continent’s interior, and Livingston referred to it
as “that damned Zambezi”.
Apparently a Mr F Monks successfully
navigated down the rapids in the early 1880’s, but as no printed report can be
found details of his dugout trip remain a mystery.
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| Local fishing dugout on the dam |
Damming the Impassable
With politics easily matching the turbulent
river, fast forward to 1956 when the Portuguese government, determined to build
a dam, sent a team of hydrologists to survey the region. The positive report back by the team
encouraged the colonial government to steam ahead with its plans. Environmental impact studies, such as they
were, served only to support the government’s objectives, being the expansion
of agricultural production, development of mining, forestry promotion, reducing
Mozambican dependency on foreign imports and uplifting the living conditions of
the local communities.
A major underlying motive at the time,
however, was to encourage an increased population of European settlers who,
alongside the physical geographical obstruction of a lake 240kms long and 31kms
wide, would act as a barrier to guerrilla forces entering Mozambique from bases
in Zambia and Malawi.
The prospect of a massive hydro-electric
scheme attracted the South African government into a joint venture with the
Portuguese, and construction began on the dam in 1969. It’s hard to comprehend
the foolhardy determination to build the biggest hydro-electric dam in Southern
Africa, in an inaccessible site on a river famous for unpredictable and
frightening floods. Politically, an
international outcry arose, forcing several global companies and banks to
withdraw expertise and funding. Labour, both
skilled and unskilled, was in short supply.
Bizarrely, the tragic deaths of seven workers finally convinced local
labour that the project was sufficiently dangerous to match the prestigious
peril of working on the South African gold mines, and they began signing on to work
at Cahora Bassa.
As if determined to shake off the intrusion
by man, the gorge delivered a climate of sweltering heat (at times reaching 60°
C) with heavy rains in the wet season; combining that with pestilential
tropical diseases such as malaria, bilharzia and yellow fever to create
indescribable hardship and difficulties for the workers.
Add to this ongoing sabotage - part of the
political upheaval signifying the approaching end of colonial Portuguese rule -
and you begin to get a picture of complete misery driven by political pride and
posturing.
Size Does Count
Costing US$500 million to build, the
contract to construct the dam was awarded to Zambeze Consorcio Hidroelectrica
Lda (ZAMCO) and included the installation of the electricity generation system
and electricity transmission. The arch
dam is 171m high and 303m wide at the crest, with a volume of 510 000 000m3.
Transport issues arising from its remote
location led to the construction in 1973 of the Caetano Bridge (now called Samora
Machel Bridge) in Tete, 440 years after the Portuguese first settled in the
town. Completion of the bridge enabled
access for the enormous construction machinery required for the building of Cahora
Bassa.
Filling of the dam commenced in December
1974 and by April 1975 the dam was virtually complete. In June of that year Hidroelectrica de Cahora
Bassa (HCB) was formed to operate the dam and power station, which has five
hydraulic turbines and a total generating capacity of 2075MW.
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A White Elephant?
However, Cahora Bassa hadn’t finished its
malevolent challenging of the project.
Two days after HCB’s formation, Mozambican independence was declared and
the Portuguese left Mozambique forever.
But while Portugal may have handed over the colony, it was adamant the
new government take responsibility for the cost of the dam, and insisted that
Portugal would retain ownership of Cahora Bassa until that debt was paid off.
The new regime signed a contract with South
African electricity giant Eskom to buy the dam’s output, only to have the Mozambique
civil war intervene in 1977, putting Cahora Bassa out of service between 1985
and 1997. The irony of the once Cahora
Bassa saboteurs, now the government, fruitlessly trying to secure the power
lines and transmitters against rebel guerrillas will not be lost on the reader.
Endless wrangling and negotiation over
decades between Mozambique and Portugal culminated in Mozambique obtaining an
85% stake in the scheme for US$ 700m in 2007. In April 2012, Portugal finally relinquished
its interest in the hydro-electric dam - 7.5% sold for US$ 42m to the
Mozambican government, and 7.5% passed to Portuguese company Redes
Energéticas Nacionais (REN - which operates the
Portuguese electricity grid), as part of a future share swap deal.
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| The wall from the top of the gorge |
‘Kebrabasa’
Will the work ever end? The mighty river is resistant to taming and
continues to flood, with politics playing out across the map - oddly
reminiscent of the scenario confronting the early European explorers. Aging facilities have already caused a costly
upgrade, and Cahora Bassa reported its first profit only in 2010.
Things are slowly looking up, however. In a press release dated 25th
November 2014, HCB reported that the 2014 annual power output of the dam had
reached 15,892 GWh,
an increase of 6.35% on the previous year.
For much of its 39 years, Cahora Bassa has
not operated at anything close to capacity; however the Mozambique government
is proposing to build a new dam, Mphanda Nkuwa, 60kms downstream, while environmentalists
are still unravelling the impact of the existing dam and trying to find
solutions.
A new dam may prove to be a wall too many.
Sources:
Zambezi
– Journey of a River. Michael Main
www.hcb.co.mz
www.iol.co.za (15 April 2012)
A.
Isaacman, C. Sneddon
“Portuguese Colonial
Intervention, Regional Conflict and Post-Colonial Amnesia: Cahora Bassa Dam,
Mozambique 1965–2002” Cornell Institute for
African Development (May 2003)
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