Africas Lakes: Atlas of Our Changing Environment

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Africas Lakes Atlas of Our Changing Environment
Ashbindu Singh
United Nations Environment Programme (UNEP)
as_at_rona.unep.org
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Africas Lakes Atlas of Our Changing Environment
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Africas Lakes Atlas of Our Changing Environment

• Objectives
• Provide visual evidence of changes taking place
  in African lakes
• Communicating scientific information to a wider
  audience in an engaging fashion
• Provide resources to educational community.
• Assumptions
• Trends over time is the most compelling
  information
• A picture is worth a thousand words
• Seeing is believing

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The Shrinking African Continent Population per
unit area
1950 - 7 people/km2
1960 - 9 people/km2
1970 - 12 people/km2
1980 - 16 people/km2
1990 - 21 people/km2
2000 - 27 people/km2
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Africas Lakes Atlas of Our Changing Environment
Forest Loss, Invasive Species, Land Degradation,
Pollution and Inefficient Irrigation taking their
toll

• CONTENTS
• Over 60 Satellite Images
• Over 40 ground photos
• 15 Environmental Maps of Africa

CONTRIBUTORS 42 Contributors from 16
Organizations and 11 Countries
Africas Lakes Atlas of Our Changing Environment
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Africas Lakes Atlas of Our Changing Environment

• Before and after satellite images
• Lesotho Highlands Water Project,
• Lake Nakuru, Kenya
• Challawa Gorge Dam, Nigeria
• Lake Kivu, Congo/Rwanda
• Lake Alaotra, Madagascar
• Lake Al Wahda, Morocco
• Lake Cahora Basa, Mozambique
• Lake Chivero, Zimbabwe
• Lake Djoudj, Senegal
• Lake Ichkeul, Tunisia
• Lake Manantali, Mali
• Lake Sibaya, South Africa
• Songor Lagoon, Ghana
• Lake Tonga, Algeria

• Case studies
• Lake Chad, Nigeria, Niger, Chad, Cameroon
• Lake Victoria, Uganda, Kenya, Tanzania
• Toshka Project, Egypt

Africas Lakes Atlas of Our Changing Environment
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Africas Lakes Atlas of Our Changing Environment

• Lack of good database makes precise number of
  lakes in Africa unknown, but according to the
  WORLDLAKE database, there are 677 lakes in Africa
  (Minnesota State alone is home to 10 000 Lakes)

• There are 15 natural lakes that cross the
  political boundaries of two or more countries in
  Africa

• There are 60 transboundary river basins in
  Africa, covering over 63 per cent of the
  continents land area

• Lake Chads surface area has shrunk by 95 per
  cent over the past 35 years

Africas Lakes Atlas of Our Changing Environment
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Africas Lakes Atlas of Our Changing Environment

• Uncontrolled damming, the withdrawal of water
  for irrigation, and climate variability are the
  major causes of drying up of Lake Tonga in Algeria

• Population growth around Lake Victoria, the
  continents largest lake, is significantly higher
  than the rest of Africa

• Some lakes in central Africa have become known
  as killer lakes, because of the catastrophic
  natural events that have occurred in their
  vicinity

Africas Lakes Atlas of Our Changing Environment
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Shrinkage of Lake Chad
Persistent drought and diversion of water has
shrunk the lake to about a tenth of its former
size

• 1972 Larger lake surface area is visible in
  this image

• 2001 Impact of drought displays a shrunken
  lake, comparatively much smaller surface area
  than in 1972 image

Africas Lakes Atlas of Our Changing Environment
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Lake Victoria Falling Water Levels Concern for
Growing Population

• Since December 2005, water levels dropped to
  alarmingly low levels

• Current water levels in Lake Victoria are below
  normal and the lowest level since September 1961

• The lake is a crucial resource to some 30 million
  people

• Lake area is the most densely populated rural
  region in the world

• An estimated 150 000 sq. km. of land have been
  affected by soil degradation of which 13 per cent
  has been severely degraded

Africas Lakes Atlas of Our Changing Environment
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Population Growth Around Lake Victoria

• The population growth around 100 km buffer zone
  of the Lake Victoria

• Population growth around Lake Victoria, East
  Africa, is the highest in Africa

• 2010 and 2015Projected

Africas Lakes Atlas of Our Changing Environment
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Lake Victoria Worlds Fastest Growing Rural Area
Around 1 200 people per sq. km. live in and
around the lake average annual income is US 250
per capita
Africas Lakes Atlas of Our Changing Environment
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Population Growth Lake Victoria vs. Africa
Africas Lakes Atlas of Our Changing Environment
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Mapping falling water levels of Lake Victoria
Current water levels are below normal and the
lowest level since September, 1961
Africas Lakes Atlas of Our Changing Environment
Source USDA 2005
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Lake Victoria Height Variations
Africas largest freshwater lake is now about a
meter lower than it was in the early 1990s
Africas Lakes Atlas of Our Changing Environment
Source USDA 2006
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Impact of Invasive Species on Lake Victoria,
Uganda
These images show water hyacinth infestation and
control of such invasive species

• 1995 Image shows several water-hyacinth-choked
  bays (yellow arrows)

• 2001 A visible reduction of Water Hyacinth
  from many of the Ugandan bays

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Lake Kivu One of Africas Killer Lakes
These images show dramatic changes before and
after the eruption of Mt. Nyiragongo in 2002

• 2001 Before the January 2002 eruption

• 2003 Shows the track of the lava flow

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Toshka Lakes Watering the Desert for Farming
These images show the desert area transformed
into vegetable plots

• 1984-87 Image of the area before the desert
  reclamation project began in mid-1990s

• 2000 Four new lakes are visible in this image,
  faint blue-green areas around the lakes are newly
  created agricultural lands

Africas Lakes Atlas of Our Changing Environment
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Toshka Lakes Watering the Desert for Farming
2005 New fields are clearly visible in the image
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Lesotho Highland Water Project in South Africa
These images show the area before and after
construction of Katse dam

• 1989 Image of the area before the completion of
  the dam in 1995

• 2001 Katse dam created an enormous reservoir,
  the extent of which can clearly be seen in this
  image

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Extensive Deforestation Around Lake Nakuru in
Kenya
These images show the land cover degradation in
the lakes catchment

• 1973 The area that hosts the worlds largest
  concentration of flamingos

• 2000 Excision of forest in the Eastern Mau
  Forest Reserve (white lines) will most likely
  lead to disappearance of upper catchment forest
  cover

Decline in lake area from 43 skm to 40 skm in 2000
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Impact of Challawa Gorge Dam Nigeria
These images show the area before and after
construction of the dam

• 1990 Image of the area before the completion of
  the dam in 1993

• 1999 Impact of flooding upstream from the dam
  colour of the water in the flooded area indicates
  high sediments

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Severe Flooding Around Lake Alaotra, Madagascar
These images show flooding over a wide area

• Flooding destroys significant portion of crops

• Intensive rice irrigation occurs at the western
  part of the lake (yellow arrows)

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Impact of Al Wahda reservoir in Morocco
These images illustrate the change in land cover

• 1987 The area before the construction of dams

• 2001 The area after the construction of large
  dams

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Cahora Basa Mozambiques Largest Dam on the
Zambezi River
These images show extraordinary changes in the
Zambezi River system as a result of the building
of Cahora Basa Dam

• 1972 The Zambezi River a few years before the
  dam construction

• 1999 This image shows part of the enormous dam
  and the lake

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Invasive Species in Lake Chivero Zimbabwe
These images show overall reduction in water weeds

• 1989 Weeds show up as green strands along the
  edges of the lake

• 2000 This image shows that water weeds remains
  a persistent problem

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Ecological Changes Around Lake Ichkeul, Tunisia
These images show the impact of damming

• 1972 Shows the three feeder rivers supplying
  the lake before they were dammed

• 2000 Shows the location of the dams (yellow
  arrows)

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Agricultural Expansion Around Lake Manantali,
Mali
These images show the expansion of irrigated
agriculture

• 1977 Shows the original meandering nature of
  the Bafing River

• 1999 Shows the expanded irrigated land and
  increase in lake water quantity

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Lake Sibaya Wetland of International
Importance in South Africa
These images show increase in cultivation around
the lake

• 1991 Lakeshore is home to the only known
  species of a rare climbing orchid

• 2001 The yellow arrows vividly show the
  increase of cultivation of marginal lands around
  the lake

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Rapid Shrinking of Lake Songor Lagoon in Ghana
These images show a conspicuous reduction in the
surface area, partly due to intensive salt
production

• 1990 Appears as solid blue mass of water some
  74 sq. km. in size

• 2000 Water area dramatically reduced to pale
  shadow

• Lake is home to fish, globally threatened
  turtles and important bird populations

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Changes In and AroundLake Tonga, Algeria
These images show the changes brought about by
damming of the feeder rivers

• 1988 Lake Tonga before the damming of feeder
  rivers

• 2000 Damming increased irrigation and
  drastically reduced the volume of water entering
  the lake

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Rejuvenation of Djoudj Sanctuary in Senegal
These images show the Djoudj Sanctuary before and
after the construction of the Diama Dam 23
kilometres from the mouth of the Senegal River

• 1979 Shows the impact of drought on the Djoudj
  Sanctuary

• 1999 Rejuvenation of the Sanctuary wetlands due
  to significant floods

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Africas Lakes Atlas of Our Changing Environment
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