Wednesday, October 7, 2009

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Lake Kyoga

Uganda
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Lake Kyoga is a shallow lake with a surface area of 4000 km2. Half a million people live on its shores as well as on some on the large masses of vegetation called sudds seen floating in the lake (see especially the 1986 image). These communities rely heavily on the lake for their livelihoods. However, in the early 2000s life on the Lake was disrupted following a rapid change in the water level as a result of El Nino rains in 1997 and 1998. The high water caused some of the sudds, along with dislodged papyrus beds and water hyacinth mats to block the lakes outlet.

The satellite images from 1974, 1986 and 2002 show the floating sudds on the lake. By 2002 many of these sudds had moved west blocking the outlet to the Nile River, leading to flooding in places surrounding the lake. The floods displaced people, destroyed infrastructure and disrupted livelihoods. Two channels were opened by Uganda’s Directorate of Water Development (DWD) in 2001-2002 and later on a team from Egypt had to dredge to allow water flow downstream.
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Nairobi

Kenya
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Following its founding in 1902 it took roughly 40 years for Nairobi to exceed a population of 100 000 people. By independence, 20 years later it had reached around 350 000 people. Rapidly increasing population has been ongoing ever since, surpassing one million in the 1980s, two million in the 1990s and now approaching three million residents. While the annual rate of growth has at times exceeded 10 per cent it has more recently decreased to below four per cent per year — still very high by global standards. Nairobi is projected to top 3.8 million by 2015.

The dramatic growth in area of intense urban settlement can be seen between the 1966 image and the 2007-2008 image mosaic. Much of Nairobi’s urban footprint is unplanned settlement driven by rapid population growth and urban poverty among other things. Sprawling informal settlements handicap the city’s delivery of social services and negatively impact the quality of life.
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Mount Elgon

Uganda
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Mount Elgon, on Uganda’s eastern border, is a long extinct volcano supporting a variety of habitats, including dense tropical hardwood and bamboo forests, as well as an assortment of grassland and riverine ecosystems. Roughly 2000 square kilometers on the Ugandan side of the mountain are managed as protected areas; the largest of these being Mount Elgon National Park – established in 1992.

Some of the densest population in the country makes its home along the park’s borders on the steep foot-slopes of the mountain. Most of these communities rely on pastoralism and subsistence agriculture; and with a growing population there is a strong demand for farmland and grazing land.

The Ugandan Government and several non-governmental agencies along with the local communities, strive to balance the livelihoods of the local people with the need to protect the important natural areas of Mt Elgon – upon which those livelihoods ultimately rely. The resettlement of local people in 1983, in an area previously managed as forest can be seen clearly seen in these images from 1973 and 2005. This resettlement proved to be quite problematic for local people and the government.

Since the mid 1980s, management of this area has taken a community based resource management approach, with improved participation and empowerment of the local comminutes. Nevertheless, continued growth of the area’s population makes striking a balance between protecting the mountain’s natural resources and meeting the needs of the local communities ever more challenging.
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Mau Forest Complex

Kenya
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In spite of its national importance, many areas of the Mau Forest Complex have been deforested or degraded, with much of the damage occurring since the 1980s. Degazettement of forest reserves and continuous widespread encroachment have led to the destruction of over 100 000 ha of forest since the late 2000s, representing roughly one-quarter of the Mau Complex’s area. This series of satellite images documents 35 years of incremental destruction of forest area, punctuated by dramatic excisions.

The Mau Forest Complex contains the catchment areas for many of Kenya’s most important rivers. The loss of forest can impact the quality and volume of water for these important rivers. Extreme land-cover changes such as these can have serious consequences both within the forest and downstream in the form of water shortages, health risks, desertification, habitat destruction, sedimentation, erosion, and even alteration of the micro-climate. This rate of forest loss is unsustainable and threatens the security and future development of Kenya.
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Loita Plains

Kenya
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The Loita Plains, northeast of world famous Masai Mara National Reserve, are an important part of the larger Serengeti-Mara Ecosystem. They are core breeding and calving grounds and wet-season grazing land for the wildebeest, whose annual migration is the primary tourism feature of the Masai Mara Reserve. The natural landscape here is tall grass savanna with some scattered acacia and dwarf shrubs. The primary human inhabitants of the Loita Plains are the Maasai, who have traditionally been nomadic pastoralists. Responding to the limited, unpredictable and seasonal rains on these grasslands the Masai like the wildebeest, traditionally migrated through the year to where the grasses provided adequate food for their cattle.

Over the past several decades, changes in land use in the Narok District have caused changes in ways of life for both the Masai and the Wildebeest. While most Masai in both Tanzania and in Kenya have taken up cultivation in recent decades, land tenure restrictions in Tanzania have tended to prevent widespread development of mechanized cultivation. In Kenya however, large mechanized wheat farms in the area surrounding Masai Mari expanded roughly 1 000 per cent between 1975 and 1995, most of them on the Loita Plains. This has reduced the available natural grasslands in this important wildebeest habitat. The Masai Mara is perhaps the most famous of Kenya’s tourist attractions and the annual migration of the wildebeest and other large mammals is one of the Mara’s most compelling features. Management of competing land uses for this vast grassland will require a careful balance if its value is to be preserved for future generations.
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Lake Wamala

Uganda
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Seventy kilometers to the west of Kampala is Lake Wamala. After being stocked in 1956 the lake was a productive fishery in the 1960s and early 1970s, providing a major source of fresh fish for the city of Kampala as well the local residents surrounding the lake. However, the lake was seriously overfished and the fishery had largely collapsed by the mid 1970s.

The shallow lake’s levels have fluctuated with changes in precipitation through the recent decades. In the 1980s its surface covered roughly 250 sq km. During the 1990s its surface shrank to roughly half that size. It has more recently recovered much of its surface area, however Lake Wamala’s future management remains a concern for those who live in its vicinity.
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Lake Naivasha

Kenya
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Unlike other lakes in Kenya’s Eastern Rift Valley, Lake Naivasha is a freshwater lake, receiving most of its inflow from the Aberdare Mountains to its east. It is a valuable freshwater resource for human uses and for a diverse population of water birds and large mammals, including hippopotamuses. The lake supports a range of economic activities including commercial flower growing, fishing, and a geothermal power plant.

In recent years, pressure on the Lake has increased as population and human activities have intensified throughout its catchment. Several of these changes can be seen in the differences between the 1973 and 2008 satellite images. The footprints of Naivasha town and Karagita have grown considerably to well above 600 000, reflecting the increased population throughout the catchment. Many commercial greenhouse flower farms have been built since the early 1980s. These are visible surrounding the lake as bright white and light blue squares of greenhouse roofs.

Designated a Ramsar Wetland of International Importance, efforts are being made to sustainably manage the lake. Nevertheless, water abstraction for agriculture; watershed deforestation; diversion of inflow from Malewa and Gilgil Rivers; nutrient, sediment, and chemical runoff into the lake; and invasive species are just some of the many concerns bearing on Naivasha’s future.
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Kampala

Uganda
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Due primarily to high rural to urban migration, Kampala’s population has grown at an average rate of 5.6 percent annually since the 1960s; expanding its urban footprint to a sprawling 197 square kilometers. Over 1.2 million people now live in the capital city. This stunning growth can be seen in the remarkable contrast between these 1974 and 2008 satellite images.

The growing population has led unplanned settlement and inadequate infrastructure for many of the City’s residents. In addition, areas of forest in and around the capital have been lost to increasing demand for charcoal. Many of the wetlands in the Kampala area have been lost to industrial and residential development. This has had a negative impact on water quality within Kampala as well as the water of Murchison Bay which has experienced periodic infestations of water hyacinth and massive algae blooms which turn the water of the bay green.
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Dadaab Refugee Camp

Kenya
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Ifo, Dagahaley, and Hagadera refugee camps are located in Dadaab town in the North Eastern Province of Kenya, near the border with Somalia. The camps date back to 1991 when civil wars erupted on a large scale in Somalia. The conflicts, along with prolonged drought, forced more than 400 000 people from Somalia to flee to Kenya and another 500 000 to other neighboring countries. The 1987 image shows a fairly intact landscape dominated by shrub vegetation characteristic of the semiarid area. In the 2000 image, the Ifo, Dagahaley, and Hagadera refugee camps stand out distinctly, revealing the presence of over 100 000 refugees and the impact of a high concentration of people on the environment. Shrublands have been reduced largely to bare spots with sparse and stunted shrubs and grasses, while riverine vegetation has also suff ered loss and degradation.
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Budongo Forest Reserve

Uganda

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A study in the Budongo Forest/Murchison Falls National Park landscape shows that there has been both woody cover decrease and increase. In areas where there has been continuous burning, woody cover species have changed from those that are less resistant to fire to those that are more resistant. The burning was mainly carried out by the local communities bordering the forest. In the northern portion of Budongo, an increase in policing of the forest area and the presence of a park entry gate has resulted in an observable decrease in burning.

Signs of fire are evident in such landscapes as dark reddish purple scars. Fire scars were evident on the 1973 image of northern Budongo. There are almost no fire scars on the 2008 image. The areas where there has been a higher control of burning are the areas which have seen an increase in woody cover.
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