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International Institute for Geo-Information Science and Earth Observation (ITC) 2008

Monitoring spatio - temporal dynamics of land cover changes in lake Naivasha drainage basin, Kenya

Okello Were, K (Kennedy)

Titre : Monitoring spatio - temporal dynamics of land cover changes in lake Naivasha drainage basin, Kenya.

Auteur : Okello Were, K (Kennedy)

Etablissement de soutenance : University of Twente International Institute for Geo-Information Science and Earth Observation (ITC)

Grade : Master of Science in Geo-Information Science and Earth Observation 2008

Résumé
Land cover is a fundamental variable that impacts on, and links many parts of, the global environment. Changes in land cover can have far-reaching ramifications at local, regional and global levels. Thus, patterns of land cover must be understood at a range of spatial and temporal scales with a view to characterizing and predicting the potential environmental impacts. This work focused on the dynamics of land cover change occurring within the Lake Naivasha drainage basin in Kenya. The area has undergone rapid land use transformations since independence to date leading to land cover changes. This in turn compromises the natural resource base, hence, the need to monitor and avail reliable data for decision making on sustainable land use. The research objectives were two-fold : to determine the probable driving forces of land use that results in land cover changes in Lake Naivasha drainage basin and ; to establish and map the magnitude, rates, nature and spatial distribution of the land cover changes that had occurred in the area. Both remote sensing and GIS techniques were employed to collect the pertinent data needed for fulfilling the research objectives. Multi-temporal satellite data (ASTER 2007 and Landsat TM 1986&1995) were acquired and field survey conducted from, which land cover sample data were collected using t he Global Positioning Systems (GPS) and mobile GIS. Data on the driving factors of land use were obtained through semi-structured interviews. The land cover sample data were then used for classification of the satellite images using object-based approach resulting in land cover maps for 1986, 1995 and 2007. These were further analyzed for changes using the post-classification technique. Since the multi- temporal remote sensing data only offered partial coverage, SPOT-NDVI data was used to delineate four representative units of the whole basin. These units were used for land cover change mapping and analysis. The analysis yielded results on the estimates of the magnitude and rates of land cover changes within the Lake Naivasha drainage basin as well as the geographic distribution of these changes. In overall, the forests, woodlands, grasslands and shrub lands showed declining trends in their rates and magnitude of change whereas the croplands and built-up land had a constant increase between 1986 and 2007. Friedman’s test was employed in the analysis of the driving factors of land use and its results concluded that the driving factors had different influences on land use in Naivasha basin. Both proximate and underlying processes constituted the driving factors of land use. These included : demographics (household sizes and numbers), market availability and prices, climate and sustenance (source of livelihood).

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Page publiée le 8 février 2018