# Presentation: 603785

## Africa’s Lakes: Atlas of Our Changing Environment

**Ashbindu Singh**

- United Nations Environment Programme (UNEP)
-  as@rona.unep.org

## Africa’s Lakes: Atlas of Our Changing Environment

## Africa’s 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”

## 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

## Africa’s Lakes: Atlas of Our Changing Environment

- Africa’s Lakes Atlas of Our Changing Environment

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

_***CONTRIBUTORS***_
**42 Contributors from 16 Organizations and 11 Countries**

**Forest Loss, Invasive Species, Land Degradation, Pollution and Inefficient Irrigation taking their toll**

## Africa’s Lakes: Atlas of Our Changing Environment

** ****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**

**Africa’s Lakes: ****Atlas of Our Changing Environment**

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

- Africa’s Lakes Atlas of Our Changing Environment

## Africa’s Lakes: Atlas of Our Changing Environment

- Africa’s 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 continent’s land area **

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

## Africa’s Lakes: Atlas of Our Changing Environment

- Africa’s 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 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**

## Shrinkage of Lake Chad

- Africa’s Lakes Atlas of Our Changing Environment

- 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

**Notes:**
Lake Chad, located at the junction of Nigeria, Niger, Chad, and Cameroon was once the sixth-largest lake in the world. Persistent droughts have shrunk it to about] a tenth of its former size. The lake has a large drainage basin—1.5 million km2 (0.6 million square miles)—but almost no water flows in from the dry north. Ninety per cent of lake’s water flows in from the Chari River. The lakebed is fl at and shallow; even before the drought, the lake was no more than 5-8 m (16-26 ft) deep. Considered a deep wetland, Lake Chad was once the second largest wetland in Africa, highly productive, and supporting a diversity of wildlife. The lake is very responsive to changes in rainfall. When rains fail, the lake drops rapidly because annual inflow is 20-85 per cent of the lake’s volume. Human diversion from the lake and from the Chari River may be significant at times of low flow, but rainfall is still the determining factor in lake level. This image set displays a continued decline in lake surface area from 22 902 km2 (8 843 square miles) in 1963 to a meager 304 km2 (117 square miles) in 2001.

## 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**

- Africa’s Lakes Atlas of Our Changing Environment

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

## 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 2015=Projected

- Africa’s Lakes Atlas of Our Changing Environment

## Lake Victoria: World’s Fastest Growing Rural Area

- Africa’s Lakes Atlas of Our Changing Environment

- Around 1 200 people per sq. km. live in and around the lake; average annual income is US$ 250 per capita

## Population Growth: Lake Victoria vs. Africa

- Africa’s Lakes Atlas of Our Changing Environment

## Mapping falling water levels of Lake Victoria

- Source: USDA 2005

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

- Africa’s Lakes Atlas of Our Changing Environment

## Lake Victoria: Height Variations

- Source: USDA 2006

- Africa’s Lakes Atlas of Our Changing Environment

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

## Impact of Invasive Species on Lake Victoria, Uganda

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

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

- These images show water hyacinth infestation and control of such invasive species

- Africa’s Lakes Atlas of Our Changing Environment

**Notes:**
Shared by Kenya, Tanzania, and Uganda, Lake Victoria is the second largest freshwater lake in the world. The infestation of Lake Victoria by water hyacinth in the 1990s disrupted transportation and fishing, clogged water intake pipes for municipal water, and created habitat for disease-causing mosquitoes and other insects. This led to the initiation of the Lake Victoria Environmental Management Project in 1994. The focus of the Project was to combat hyacinth infestations on the lake, particularly the region bordered by Uganda, which was one of the most severely affected areas. The 1995 image shows several water-hyacinth-choked bays: Murchison Bay near Gaba; large parts of Gobero and Wazimenya Bays; an area outside Buka Bay; and near Kibanga Port (yellow arrows). Initially, water hyacinth was controlled by hand, with the plants being manually removed from the lake. But re-growth quickly occurred. A more recent control measure has been the careful introduction of natural insect predators of water hyacinth. As the 2001 image shows, this approach seems to have been successful, as the floating weeds have disappeared from all the locations noted above.

## Lake Kivu: One of Africa’s  “Killer Lakes”

- Africa’s Lakes Atlas of Our Changing Environment

**Lake Kivu: One of Africa’s  ****“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

**Notes:**
Lake Kivu on the Congo-Rwanda border is the highest lake in Africa at 1 459 m (4 788 ft).  Beneath the lake lie vast reserves of methane gas which has not been exploited. Lake Kivu is also an important tourist center. These satellite images of Lake Kivu show dramatic changes before and after the eruption of Mt. Nyiragongo in January 2002. The 2003 image clearly shows the track of the lava flow, which traveled through Goma town and into the northeastern part of the lake, contaminating its waters. Lake Kivu is one of Africa’s “killer lakes,” containing a volatile combination of methane and carbon dioxide gases with the capacity to kill thousands of people.

## Toshka Lakes: Watering the Desert for Farming

- Africa’s Lakes Atlas of Our Changing Environment

- 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

**Notes:**
Egypt’s Toshka Project has transformed part of the country’s scorching hot southern desert into a region dotted by lush, neatly tended vegetable plots that are supplied with water and fertilizer by drip irrigation systems. These images, from 1984 and 2000, document the changes and success Egypt has had in this desert reclamation project, which was begun in the mid-1990s and aimed to double the size of Egypt’s arable land in fifteen years’ time.  The project created four new lakes in the desert by drawing water through a concrete-lined canal from Lake Nasser, which was formed by damming the Nile River at Aswan. The water flows through the canal into the Toshka Depression, where it forms the lakes visible in the 2000 image. The faint blue-green areas visible around some of the lakes are agricultural lands, newly created by irrigation. While providing people with new arable land on which crops can be grown, the Toshka Project’s environmental impacts are still under study.

## Toshka Lakes: Watering the Desert for Farming

- Africa’s Lakes Atlas of Our Changing Environment

**Toshka Lakes: ****Watering the Desert for Farming**

- 2005: New fields are clearly visible in the image

## Lesotho Highland Water Project in South Africa

- Africa’s Lakes Atlas of Our Changing Environment

**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

**Notes:**
The Lesotho Highlands Water Project (LHWP) is one of the largest infrastructure projects ever undertaken on the African continent. The project is designed to divert water from Lesotho’s Maloti Mountains to South Africa’s urban and industrial Gauteng Province. While South Africa is set to benefit from an increased supply of much-needed water, Lesotho would gain through the generation of hydroelectric power and profits from the sale of water. An 82-km (51-mile) water transfer-and-delivery system is already in place for delivering water to South Africa. On completion of the full project, a total of four dams will be placed in key locations. However, many questions remain unanswered about the social and environmental impacts the completed dams will have. The first dam in the multi-dam scheme, called Katse, located on the Orange River, closed its gates in 1995, creating an enormous reservoir along with serious social and environmental concerns. These two images provide a comparison of the area before and after completion of the Katse dam. The effects and extent of the Katse Dam can clearly be seen in the 2001 image.

## Extensive Deforestation Around Lake Nakuru in Kenya

- Africa’s Lakes Atlas of Our Changing Environment

**Extensive Deforestation Around ****Lake 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

**Notes:**
Lake Nakuru is located in the Eastern Rift Valley in southwest Kenya. Lake Nakuru National Park is the second most visited protected area in Kenya. It hosts the world’s largest concentration of flamingos, as well as many of the animal species that make Kenya a highly valued tourism destination, including lions, leopards, rhinoceros, and water buffalo. In its total area of 188 km2 (73 square miles), there are over 450 bird species and 56 mammal species. Recognized as a wetland of international importance, Lake Nakuru was declared a Ramsar Site in 1990. The threat of land cover degradation in the catchments of the lake is likely to increase flow fluctuation and decrease water quality. These images show the land cover degradation in the lake’s catchment between 1973 and 2000. In 2001, the Government of Kenya announced its intention to excise 353 km2 (136 square miles) of forest in the Eastern Mau Forest Reserve (area with white boundary in the 2000 image). As a result, most of the forest cover in the upper catchment of the main rivers that feed Lake Nakuru will disappear.

## Impact of Challawa Gorge Dam Nigeria

- Africa’s Lakes Atlas of Our Changing Environment

**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

**Notes:**
The Challawa Gorge Dam, completed in 1993 on the Challawa River, is the second-largest of the 23 dams along rivers in Nigeria’s Hadejia-Jama’are River Basin. Though the dam has improved the water supply for irrigation, heavy rains cause the river to break its banks upstream from the dam; farmers are driven out as the rising water floods their farms and adjoining lands. Areas downstream from the dam, on the other hand, do not receive enough water to maintain the wetlands that border the river. Under these conditions, the soil dries out and overgrazing occurs, which in turn leads to wind erosion of the topsoil.  This satellite image pair gives a comparison of the area before and after construction of the dam. The 1999 image shows the degree to which flooding upstream from the dam impacts the landscape, and how the lack of water downstream negatively affects riverine wetlands and cropland. The colour of the water in the flooded area is also indicative of high-sediment content.

## Severe Flooding Around Lake Alaotra, Madagascar

- Africa’s Lakes Atlas of Our Changing Environment

**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)

**Notes:**
Lake Alaotra is a shallow, reed-fringed lake that lies in a tectonic basin 40 km (25 miles) long and 9.5 km (6 miles) wide. The images from March 2005 show extensive flooding of the lake, especially along its western and southern shores. Heavy rains, unusual for the time of year, caused severe flooding across Madagascar, destroying an estimated ten per cent of the region’s rice crop. This pair of MODIS images shows flooding over a wide area, including Lake Alaotra (outlined in white). In the images, vegetation shows as bright green, water as shades of blue, and clouds as light blue. Intensive rice irrigation occurs at the western part of the lake (yellow arrows).

## Impact of Al Wahda reservoir in Morocco

- Africa’s Lakes Atlas of Our Changing Environment

**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

**Notes:**
The center of the Kingdom of Morocco is occupied by the high Atlas Mountains which separate fertile coastal plains from inland pre-Saharan semi-arid areas. In Morocco, the rain rate varies strongly from one region to the other, when going southward or eastward. To reduce the effects of that disparity, Morocco has adopted a policy for transferring water from regions with surplus towards regions with water deficits. The dam policy initiated at the beginning of the 1960s has  had beneficial fallouts for social and economic development of the country.  There are now 110 large dams in Morocco, with a storage capacity of 158 000 millions of m3. These two satellite images illustrate the change in land cover before and after the Al Wahda reservoir was  constructed.

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

- Africa’s Lakes Atlas of Our Changing Environment

**Cahora Basa: Mozambique’s 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

**Notes:**
Cahora Basa Reservoir in Tete Province of Mozambique is the site of the country’s largest dam on the Zambezi River. These satellite images show spectacular changes in the Zambezi riverine system over the past three decades. The 1972 image shows the Zambezi River a few years before the Cahora Basa Dam was constructed, while the 1999 image shows part of the enormous dam and the lake. The eastern/right tip of the river is visible in both images, entering into a narrow gorge, which provides an obvious location for a power-producing barrage (dam) of this size. Although the construction of Cahora Basa was seen as a strategic move to meet the region’s growing energy needs, it has also reduced the extent of annual flooding on the Zambezi River downstream—in turn reducing the size of the floodplains on which local communities grow their crops.The atlas links many ecological and other changes that have occurred since the natural river flow was changed. These include the decline of flood-dependent grasslands, the drying out of mangroves and the fall in water levels on the tributary Shire River which has significantly affected navigation.

## Invasive Species in Lake Chivero Zimbabwe 

- Africa’s Lakes Atlas of Our Changing Environment

**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

**Notes:**
Lake Chivero holds about 250 000 million litres (264 000 million quarts) of water and is approximately 26 km2 (10 square miles) or 2 632 ha. Beginning in the mid 1980s, the lake became progressively eutrophic, after a recovery period from a previous eutrophication phase in the mid 1960s. While these two images suggest an overall reduction of the presence of invasive water weeds in Lake Chivero between 1989 and 2000, there is evidence that this remains a persistent problem. The weeds show up as green strands along the edges of the lake. Like most of Zimbabwe’s freshwater bodies, freeing Lake Chivero from the weed menace will require long-term eradication strategies, continuous monitoring, and a comprehensive integrated water basin management programme.

## Ecological Changes Around Lake Ichkeul, Tunisia 

- Africa’s Lakes Atlas of Our Changing Environment

**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)

**Notes:**
Lake Ichkeul is the last remaining lake in a chain that once extended across North Africa.
The construction of three dams on rivers supplying Lake Ichkeul and its marshes has cut off almost all inflow of fresh water, causing a destructive increase in the salinity of the lake and marshes. The 1972 image shows the three feeder rivers supplying the lake before they were dammed. The 2000 image shows the location of the dams (yellow arrows) built to increase irrigation and water supplies to local communities. However, the decreasing water discharge into the lake caused by the damming lead to prolonged drought of the surrounding marshlands. Changes to the prevalent vegetation and other serious ecological changes have inevitably led to a decrease in the number of birds using the lakeshores as a breeding site.

## Agricultural Expansion Around Lake Manantali, Mali

- Africa’s Lakes Atlas of Our Changing Environment

**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

**Notes:**
Lake Manantali on the Bafing River contributes to power generation and irrigation in the surrounding areas. These two images illustrate some of the physical changes that have occurred in the Bafing riverine system since the construction of the Manantali Dam, which began in 1981. The 1977 image shows the original meandering nature of the Bafing River, which annually deposited rich fluvial soils used by local people for growing sorghum and other crops on its floodplains. The 1999 image shows the extent of irrigated agriculture in the surrounding area, which rapidly expanded after the dam was filled between 1986 and 1988. The increase in water quantity is also clearly visible in 1999 image.

## Lake Sibaya:  Wetland of International Importance in South Africa

- Africa’s Lakes Atlas of Our Changing Environment

**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

**Notes:**
Lake Sibaya is narrowly separated from the sea by a range of high forested coastal dunes.
The lake is home to large hippopotamus and crocodile populations, although their numbers have dropped over the last fifteen years due principally to poaching. The lakeshore is also home to the only known population of a rare climbing orchid. The yellow arrows vividly show the increase in cultivation of marginal lands around Lake Sibaya. Agriculture in the lake catchment and along its drainage lines may cause erosion, eutrophication, pollution, and the drying up of wetlands around the lake raising concerns among environmentalists. Although Lake Sibaya has been designated a wetland of international importance, there has been little effort by communities around the lake to practice sustainable management or to protect the rare species found in the region.

## Rapid Shrinking of Lake  Songor Lagoon in Ghana

- Africa’s Lakes Atlas of Our Changing Environment

**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

**Notes:**
Songor Lagoon is one of the major lagoon systems, associated with the Volta river estuary, with a surface area of about 115 km2 (44 square miles). These two images show a conspicuous reduction in the surface area of Songor Lagoon—and the environmental health of the wider region. The deep blue open-water area is dramatically reduced in the 2000 image, with large areas of bare ground exposed. Although some of these changes may reflect seasonal or annual rainfall variability, closer analysis indicates a more permanent and significant decline in the lagoon’s surface area. The two main reasons for this appear to be salt extraction at the western end of the lagoon and diversion of feeder streams for irrigation.

Intensive salt production and evaporation at the western end, seen as dark blue and turquoise squares, is thought to be largely to blame. Agricultural extraction of water from feeder rivers like the Sege and Zano may be also taking its toll.

## Changes In and AroundLake Tonga, Algeria

- Africa’s Lakes Atlas of Our Changing Environment

**Changes In and Around****Lake 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

**Notes:**
These two images show the dramatic human induced changes in and around Lake Tonga over the past 15 years. The damming of the feeder rivers of Lakes Tonga and Oubeira (shown in the bottom part of the 2000 image) has resulted in increasing irrigation around the dams and a drastic reduction in the volume of water entering the lake. The 2000 image was acquired during the rainy season, showing an increase in the water volume after the 1999 drought, which had left the lake virtually dry. The widespread ecological changes caused by the construction of dams around Lake Tonga should serve as an eye-opener to the community. Environmental Impact Assessments of the area could assist African policymakers with information to make informed choices about future projects.

## Rejuvenation of Djoudj Sanctuary in Senegal

- Africa’s Lakes Atlas of Our Changing Environment

**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

## Africa’s Lakes: Atlas of Our Changing Environment

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