Monitoring the extent and impacts of watershed urban development in the Lake Victoria Basin, Kenya, using a combination of population dynamics, remote sensing and GIS techniques

Abstract

Abstract Several urban centres of different sizes have developed over time, and continue to grow, within the basin of Lake Victoria. Uncontrolled urban development, especially along the lake shore, puts environmental pressure on Lake Victoria and its local ecosystem. This study sought to monitor the extent and impacts of urban development (as measured by population growth and built-up land use/land cover) in the Lake Victoria basin, Kenya, between 1978 and 2018. Remote sensing and GIS-based land use/land cover classification was conducted to extract change in built-up areas from Landsat 3, 4, 5 and 8 satellite imagery obtained for the month of January at intervals of ten years. Change in population distribution and density was analysed based on decadal census data from the Kenya National Bureau of Statistics between 1979 and 2019. A statistical regression model was then estimated to relate population growth to built-up area expansion. Results indicate that the basin’s built-up area has expanded by 97% between 1978 and 2018 while the population increased by 140% between 1979 and 2019. Urban development was attributed to the rapidly increasing population in the area as seen in a positive statistical correlation (R2=0.5744) between increase in built-up area and population growth. The resulting environmental pressure on the local ecosystem has been documented mainly in terms of degradation of lake water quality, eutrophication and aquatic biodiversity loss. The study recommends the enactment and implementation of appropriate eco-sensitive local legislation and policies for sustainable urban and rural land use planning in the area. This should aim to control and regulate urban expansion especially in the immediate shoreline areas of the lake and associated riparian zones.