Akosombo Dam is a hydroelectric dam of the Volta River in southeastern Ghana
in the Akosombo gorge and part of the Volta River Authority. The
construction of the dam flooded part of the Volta River Basin, and the
subsequent creation of Lake Volta. Lake Volta is the world's largest
man-made lake, covering 8,502 square kilometres (3,283 sq mi), which is 3.6%
of Ghana's land area.
The primary purpose of the Akosombo Dam was to provide electricity for the
aluminum industry. The Akosombo Dam was called "the largest single
investment in the economic development plans of Ghana". Its original
electrical output was 912 MWe, which was upgraded to 1,020 MW in a retrofit
project that was completed in 2006.
The flooding that created the Lake Volta reservoir displaced many people and
had a significant impact on the environment.
The dam was conceived in 1915 by
geologist Albert Ernest Kitson, but no plans were drawn until the 1940s.
The development of the Volta River Basin was initially proposed in 1949, but
because they did not have sufficient funds, the American company Valco
loaned them enough so that the dam could be built. Formerly known as the
Gold Coast until 1957, when Ghana became the first sub-Saharan nation to
gain its independence from colonial rule. At that time, Ghana’s limited
economy was sustained solely by the country’s cocoa production. As a newly
independent country, Ghana became motivated to expand the economy through
industrial development. The elected Prime Minister of independent Ghana, Dr.
Kwame Nkrumah, adopted the Volta River hydropower project to grandly
represent the beginning of a new and growing economy.
The final proposal outlined the building of an aluminum smelter at Tema, a
dam constructed at Akosombo to power the smelter, and a network of power
lines installed through southern Ghana. The aluminum smelter was expected to
eventually provide the revenue necessary for establishing local bauxite
mining and refining, which would allow aluminum production without importing
foreign alumina. Development of the aluminum industry within Ghana was
dependent upon the proposed hydropower.
The proposed project’s aluminum smelter was overseen by the American
company, Kaiser Aluminum, and is operated by the Volta Aluminum Company (Valco).
The smelter received its financial investment from Valco shareholders, with
the support of the Export-Import Bank of Washington. However, Valco did not
invest without first requiring insurances from Ghana’s government, such as
company exemptions from taxes on trade and discounted purchases of
electricity. The dam, on the other hand, received its funding through loans
provided by the World Bank, and support from both the U.S. and the U.K.
These loans came to a total of about $40 million, while the government of
Ghana supplied the other $69 million necessary for constructing the
hydropower plant at Akosombo. The estimated total cost of the project, in
its entirety, was estimated at $258 million.
In 1961, the Volta River Authority (VRA) was established by Ghana’s
Parliament through the passage of the Volta River Development Act. The VRA’s
fundamental operations were structured by six Board members and Dr. Nkrumah
as Chairman. The VRA’s primary task is to manage the development of the
Volta River Basin, which included the construction and supervision of the
dam, the power station and the power transmission network. The VRA is
responsible for the reservoir impounded by the dam, the fishing within the
lake, lake transportation and communication, and the welfare of those
surrounding the lake.
The dam was built between 1961 and 1965. Its development was undertaken by
the Ghanaian government and funded 25% by the International Bank for
Reconstruction and Development of the World Bank, the United States, and the
The construction of the Akosombo dam resulted in the flooding of part of the
Volta River Basin and its upstream fields, and in the creation of Lake Volta
which covers 3.6% of Ghana’s total land area. Lake Volta was formed between
the years of 1962 and 1966, and necessitated the relocation of about 80,000
people into 52 resettlement villages two years prior to the lake’s
completion; the resettlement program was under the direction of the VRA. The
80,000 people, that represented 1% of the population, made up 700 villages
prior to resettlement. Two percent of the resettlement population were
riparian fishers and most were subsistence farmers. The Eastern Region of
Ghana and the populations incorporated within its districts, was most
subject to the project’s effects.
In the beginning of 2007, there were concerns over the electricity supply
from the dam due to low water levels in the Lake Volta reservoir. Some
sources said this was due to problems with drought that are a consequence of
global warming. During the latter half of 2007 much of this concern was
abated when heavy rain fell in the catchment area of Volta River. In 2010
the highest ever water level was recorded at the dam. This necessitated the
opening of the flood gates, and for several weeks water was spilled from the
lake causing some flooding downstream.
The dam provides
electricity to Ghana and its neighboring West African countries, including
Togo and Benin. Intially 20% of Akosombo Dam's electric output (serving 70%
of national demand) was provided to Ghanains in the form of electricity, the
remaining 80% was generated for the American-owned Volta Aluminium Company (VALCO).
The Ghana Government was compelled, by contract, to pay for over 50% of the
cost of Akosombo’s construction, but the country was allowed only 20% of the
power generated. Some commentators are concerned that this is an example of
neo-colonialism. In recent years the production from the VALCO plant has
declined with the vast majority of additional capacity in Akosombo used to
service growing domestic demand. The dam is 660 metres (2,170 ft) wide and
114 metres (374 ft) high. It cost £130 million to build.
The Akosombo Dam benefited some
industrial and economic activities from the addition of lake transportation,
increased fishing, new farming activities along the shoreline, and tourism.
The power generated has provided for primary interests within Ghana, while
also supplying power to the neighboring countries of Togo and Benin. Ghana’s
industrial and economic expansion triggered a higher demand for power,
beyond the Akosombo HEP capabilities. By 1981, a smaller dam was built at
the town of Kpong, downstream from Akosombo and further upgrades to Akosombo
have become necessary for maintaining hydropower output. Initially, the
dam’s power production capabilities greatly overreached the actual demand;
while, the demand since the dam’s inception has resulted in the doubling of
hydropower production. Increasing demands for power exceed what can be
provided by the current infrastructure. Power demands, along with unforeseen
environmental trends, have resulted in rolling blackouts and major power
outages. A trend of lower lake levels has been observed, sometimes below the
requirement for operation of the Akosombo dam.
In the time following the construction
of the dam at Akosombo, there has been a steady decline in agricultural
productivity along the lake and the associated tributaries. The land
surrounding Lake Volta is not nearly as fertile as the formerly cultivated
land residing underneath the lake, and heavy agricultural activity has since
exhausted the already inadequate soils. Upstream agricultural systems are
losing soil fertility without the periodic floodings that brought nutrients
to the soil before the natural river flow was halted by the dam. The growth
of commercially intensive agriculture has produced a rise in fertilizer
run-off into the river. This, along with run-off from nearby cattle stocks
and sewage pollution, has caused eutrophication of the river waters. The
nutrient enrichment, in combination with the low water movement, has allowed
for the invasion of aquatic weeds. These weeds have become a formidable
challenge to water navigation and transportation.
The presence of aquatic
weed along the lake and within the tributaries has resulted in even greater
detriment to local human health. The weeds provide the necessary habitat for
black-fly, mosquitoes and snails, which are the vectors of water-borne
illnesses such as bilharzia, river blindness and malaria. Since the
instalment of the dam, these diseases have increased remarkably. In
particular, resettlement villages have showed an increase in disease
prevalence since the establishment of Lake Volta, and a village’s likelihood
of infection corresponds to its proximity to the lake. Children and
fishermen have been especially hard hit by this rise of disease prevalence.
Additionally, the degradation of aquatic habitat has resulted in the decline
of shrimp and clam populations. The physical health of local communities has
been diminished from this loss of shellfish populations, as they provided an
essential source of dietary protein. Likewise, the rural and industrial
economies have experienced the financial losses associated with the
decimation of river aquaculture.
Increased human migration within the
area has been driven by poverty and unfavorable resettlement conditions.
This migration enabled the contraction of HIV and has since led to its
heightened prevalence within Volta Basin communities. The districts of Manya
Krobo and Yilo Krobo, which lie within the southwest portion of the Volta
Basin, are predominately indigenous communities that have attained a
disproportionate prevalence of HIV. The situation underlines the strength of
the local factors upon these districts. Commercial sex work was established
in response to the thousands of male workers that were in the area for
building the dam. Ten percent of the child-bearing females from these two
districts migrated out of their districts during this time. In 1986, “90% of
AIDS victims in Ghana were women, and 96% of them had recently lived outside
the country”. The Akosombo Dam and other dams of the Volta River Hydro
Development Project increased substantially the conditions for the spread of
Future conditions are likely to worsen.
Earthquakes have already become more common due to the crustal
re-adjustments from the added weight of the water within Lake Volta. There
is an eastward shift of the river’s mouth from the changes to the river’s
delta zone and this has led to continuing coastal erosion. The changes in
the river hydrology have altered the local heat budget which has caused
microclimatic changes such as decreasing rain and higher mean monthly
temperatures. All of these larger scale environmental impacts will all
further compound the problems surrounding disruptions to local economic
activities and associated, difficult human welfare conditions.