dam

1. LOCATION OF AKOSOMBO DAM
• Located at
Volta river in
south-eastern
Ghana on
Volta river
Basin.

2. HISTORY
• The building of the Akosombo dam follows almost a period of two
decades of planning which began in 1947 when the first feasibility
studies were conducted on the potential for Volta river as a
hydropower source.
• The actual construction of the dam took place within1962-1972
under the management of the Volta River Authority (VRA) .
• Jointly financed by government of Ghana, the World Bank,
the United States, and the United Kingdom.
• There were three phases of the project, phase one was the
installation of 588MW unit of electricity which was completed in
1966m. The second phase involved an addition of 304MW
electricity which resulted in total of 912 MW at the Akosombo dam.
The last phase of the project was the setting up of a smaller HEP
dam, 21km downstream, at Kpong

3. DESIGN
• Height: 114 m
• Base Width: 366 m
• Length : 660 m
• Structural Volume : 7,991,000 m3
• Rock-fill Embankment Dam
• Dam impounds the lake Volta received the flows from three rivers
Oti, Black Volta and White Volta and discharges into the lower
Volta river and then the Atlantic Ocean
• The reservoir, Lake Volta, is the largest man-made lake in the world
by surface area (8502 m2) with a volume of 148 km3 at its peak of
278 feet.
• Consists of six 230,000 hp Francis turbines which are supplied with
water via a 112–116 m long and 7.2 m diameter penstock with a
maximum of 68.8 m of hydraulic head afforded.
• A total of 1072MW of electricity is generated by the Akosombo
HEP as per VRA, 2010.

4. OBJECTIVE
• To make VALCO (Volta Aluminum Company)
energy sufficient so that its activity which is
mainly aluminum smelting would be proceed
without interruption.
• To supply electricity for both domestic and
industrial use and also export to the basin sharing
countries (Benin and Togo).
• To provide opportunities for large-scale irrigation,
modernization of agriculture, promotion of
factories and industries, and the establishment of
tourist facilities.

5. SOCIO-ECONOMIC BENEFITS
• The Akosombo HEP provides over 85% of all electricity
generated in Ghana leads to economic and industrial
development in Ghana.
• Ghana’s economy is twice the average of the West African
sub region
• The creation of the Volta Lake led to increase in fishing stock
• Farming activities is also intensified along the 5500 km
shoreline especially locations downstream of the lake as a
result of water availability for the purposes of irrigation.
• Navigation on the Volta river has changed significantly
serving as a mean for transportation for goods.
• The direct tourism impact resulting from the lake includes
opening up part of hitherto inaccessible attractions to both
local and international travellers.

6. EFFECT ON ECOLOGY
• There has been a steady decline in agricultural productivity along the
lake and the associated tributaries.
• Downstream agricultural systems are losing soil fertility without the
periodic flooding that brought nutrients to the soil before the natural
river flow was halted by the dam.
• The land surrounding Lake Volta is not nearly as fertile as the
formerly cultivated land residing underneath the lake.
• Heavy agricultural activity has exhausted the already because of
inadequate soils.
• The growth of commercially intensive agriculture has produced a rise
in fertilizer run-off into the river leads to eutrophication of the river
waters.
• The nutrient enrichment, in combination with the low water
movement, has allowed for the invasion of aquatic weeds which
creates a formidable challenge to water navigation and transportation

7. CHALLENGES ON SOCIAL ACTIVITY
• Displacement of 80,000 people across 700 villages in low lying
areas and resettle them into 52 new villages lead to the lost of the
original communities resulted in many socio-physiological problems
in the communities.
• The Volta lake creation leads to a loss of 3.6% of the total land
surface of Ghana including forest land to the reservoir.
• As a result of less arable land to farm the men switch to fishing
while most of the women were involved in prostitution as a
profession to satisfy the male workers whom were building the
dam..
• For fish and other aquatic biota, due to the ability of the dam to alter
or blocking the migration resulting in genetic disconnect between
species population.
• Injustice to the communities upstream and downstream is that it
took three decades to be connected to the national electricity grids.

8. CHALLENGES ON ECONOMIC ACTIVITY
• The upstream communities and downstream communities
are among the poorest in the country lacking access to basic
necessities like hospital, roads, proper sanitation and water
facilities.
• The lost land lead to decline in the primary economic
activities of crop and livestock farming for most of the
communities both downstream and upstream of the dam.
• The extensive human migration and degradation of natural
resources within the Volta-basin area, are the products of
poverty in conjunction with population pressure.
• the rural and industrial economies have experienced the
financial losses associated with the decimation of
river aquaculture.

9. IMPACT ON HUMAN WALFARE
• The presence of aquatic weeds provide the necessary
habitat for black-fly, mosquitoes and snails, which are the
vectors of water-borne illnesses such as bilharzia ( 2% to
32% at downstream and 0.5% to 27.4% in upstream), river
blindness and malaria (increased by an average of 10%
both upstream and downstream ).
• Children and fishermen have been especially hard hit by
this rise of disease prevalence.
• This migration enabled the contraction of HIV and has
since led to its heightened prevalence within Volta Basin
communities

10. IMPACT ON GEOLOGY
• Increase in seismic activities (4 major earthquakes of magnitude 5 or
higher have been recorded in the area) around the dam since the
construction of the lake.
• Believing that earthquakes are due to the overloading of the
geological bedrock underlying the lake with which is triggering the
active Akwapim fault.
• Sediments load have decrease by about 60mg/l downstream of the
dam as a result of the impoundment.
• The lack of sediment has lead to the erosion of the coastline in the
neighbouring Togo and Benin at a rate of 10-15m/y.
• Morphology of the delta have shifted 12 km eastward from the
original lower Volta entre point to the sea leading to coastal erosion
at Ada.
• In accordance with the behaviour of tropical dam microclimate the
temperature and rainfall in the south eastern part of Ghana is higher
than the average in other parts of the basin.

11. CONTROVERSIES