Dynamics of landuse/cover changes and degradation of Nairobi City, Kenya

Landuse/cover in Nairobi City is changing rapidly because of the increased interactions of human activities with the environment as population increases. We used multi-temporal Landsat images (1976, 1988 and 2000) together with physical and socio-economic data in a post-classification analysis with GIS to map landuse/cover distribution and to analyse factors influencing the landuse/cover changes for Nairobi City. An unsupervised classification approach, which uses a minimum spectral distance to assign pixels to clusters, was used with the overall accuracy ranging from 87 per cent to 90 per cent. Landuse/cover statistics revealed that substantial landuse/cover changes have taken place and that the built-up areas have expanded by about 47 km(2) over the study period (1976-2000). Forests have decreased substantially while agricultural lands have been on the increase. Rapid economic developments together with the increasing population were noted to be the major factors influencing rapid landuse/cover changes. Urban expansion has replaced agricultural farmlands and other natural vegetation, thereby affecting habitat quality and leading to serious environmental degradation. The random, unplanned growths of environmentally degraded squatter settlements were noted to be emerging in the rural fringes. Successful planning of Nairobi's development will require reliable information about landuse/cover changes and factors influencing such changes. Copyright (c) 2006 John Wiley & Sons, Ltd.