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Ashbindu Singh Africa’s Lakes: Atlas of Our Changing Environment United Nations Environment Programme (UNEP) [email protected] Africa’s Lakes: Atlas of Our Changing Environment Objectives Provide visual evidence of changes taking place in African lakes;

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Ashbindu Singh

Africa’s Lakes: Atlas of Our Changing Environment

United Nations Environment Programme (UNEP)

[email protected]


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Africa’s Lakes: Atlas of Our Changing Environment


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  • 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”

Africa’s Lakes: Atlas of Our Changing Environment


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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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Africa’s 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

Africa’s LakesAtlas of Our Changing Environment


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Africa’s 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

Africa’s LakesAtlas of Our Changing Environment


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1970

1980

1990

1960

  • 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)

Africa’s Lakes: Atlas of Our Changing Environment

  • 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 continent’s land area

  • Lake Chad’s surface area has shrunk by 95 per cent over the past 35 years

Africa’s LakesAtlas of Our Changing Environment


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2015

2000

2005

2010

PROJECTED

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

Africa’s Lakes: Atlas of Our Changing Environment

  • Population growth around Lake Victoria, the continent’s 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

Africa’s LakesAtlas 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

Africa’s LakesAtlas 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

Africa’s LakesAtlas of Our Changing Environment


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Population Growth Around PopulationLake 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 2015=Projected

Africa’s LakesAtlas of Our Changing Environment


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Lake Victoria: PopulationWorld’s 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

Africa’s LakesAtlas of Our Changing Environment


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Population Growth: PopulationLake Victoria vs. Africa

Africa’s LakesAtlas of Our Changing Environment


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Mapping falling water levels of PopulationLake Victoria

Current water levels are below normal and the lowest level since September, 1961

Africa’s LakesAtlas of Our Changing Environment

Source: USDA 2005


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Lake Victoria: Height Variations Population

Africa’s largest freshwater lake is now about a meter lower than it was in the early 1990s

Africa’s LakesAtlas of Our Changing Environment

Source: USDA 2006


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Impact of Invasive Species on Lake Victoria, Uganda Population

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

Africa’s LakesAtlas of Our Changing Environment


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Lake Kivu: One of Africa’s Population“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

Africa’s LakesAtlas of Our Changing Environment


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Toshka Lakes: PopulationWatering 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

Africa’s LakesAtlas of Our Changing Environment


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Toshka Lakes: PopulationWatering the Desert for Farming

2005: New fields are clearly visible in the image

Africa’s LakesAtlas of Our Changing Environment


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Lesotho Highland Water Project in South Africa Population

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

Africa’s LakesAtlas of Our Changing Environment


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Extensive Deforestation Around PopulationLake Nakuru in Kenya

These images show the land cover degradation in the lake’s catchment

  • 1973: The area that hosts the world’s 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

Africa’s LakesAtlas of Our Changing Environment


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Impact of Challawa Gorge Dam PopulationNigeria

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

Africa’s LakesAtlas of Our Changing Environment


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Severe Flooding Around PopulationLake 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)

Africa’s LakesAtlas of Our Changing Environment


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Impact of Al Wahda reservoir in Morocco Population

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

Africa’s LakesAtlas of Our Changing Environment


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Cahora Basa: Mozambique’s Largest Dam on the Zambezi River Population

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

Africa’s LakesAtlas of Our Changing Environment


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Invasive Species in Lake Chivero Zimbabwe Population

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

Africa’s LakesAtlas of Our Changing Environment


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Ecological Changes Around PopulationLake 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)

Africa’s LakesAtlas of Our Changing Environment


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Agricultural Expansion Around PopulationLake 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 PopulationImportance 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

Africa’s LakesAtlas of Our Changing Environment


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Rapid Shrinking of Lake PopulationSongor 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 Around PopulationLake 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 PopulationSanctuary 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

Africa’s LakesAtlas of Our Changing Environment


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Thank You! Population

Africa’s Lakes: Atlas of Our Changing Environment

Free Downloads:

www.na.unep.net

Purchase:

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