Spatial analysis of informal settlement sprawl and its environmental impact: a case study of Kibera
One of the United Nations Millennium Development Goals is to achieve significant improvement in lives of at least 100 million slum dwellers by the year 2020 (UN Habitat, 1990). This requires identification of slum settlements and study of their spatial expansion. Kibera the biggest slum in Nairobi has continued to expand spatially causing conflicts in land use and a host of environmental problems. This study was carried out to analyze the spatial sprawl of Kibera over time and space through the use of satellite imageries. Main research objective was to establish the pattern of spatial expansion of Kibera through the use of remotely sensed satellite imageries. Geographic Information System (GIS) was applied in manipulation of data and various analyses on the imageries. Factors which have influenced spatial expansion of Kibera were evaluated through interview data collected from selected respondents in Gatwekera village of Kibera. GIS and Remote Sensing techniques were used to study the spatial sprawl of Kibera and to identify the land use and land cover changes that had occurred, in addition to determining environmental impact of the slum growth. The study established that Kibera has been expanding over time due to high immigration rate and this spatial expansion has been accompanied by changes in land cover and land use. The spgtial sprawl has seemed to be of a definite pattern; majorly along the railway line and Muitini River and its tributaries traversing the settlement. In 1976 more than- half of Kibera was under forest cover, continued sprawl has slowly led to destruction of forest cover to create room for building houses which .now occupy over 90% of Kibera land area. Other impacts include: overcrowding, lack of clean water, toilet facilities and poor sanitation. This study therefore recommended that adequate legislative measures be put in place to contain further spatial sprawl of Kibera into the forest reserve and neighbouring areas. High resolution QuickBird satellite imageries t should also be used to constantly monitor the state of Kibera and the environmental hotspots for chanqe, Low-cost high-rise buildings to be put up and essential services: water, sanitation, toilet facilities be provided.