Temporal and spatial patterns of urban sprawl and their implications on environmental planning in Mbarara municipality

Abstract

The study was aimed at assessing the dynamics of land conversions for urban development and their impact on environmental planning in addition to assessing the characteristics of urban sprawl in Mbarara Municipality, Uganda. To determine the dynamics of land conversion for urban development, Landsat images for the years 1984, 1999 and 2014 were classified using multi-spectral classification techniques to enable the creation of land cover maps. Population and built-up area density were used as a measure of sprawl for the study area. Interviews with key informants were useful in the identification of major environmental concerns brought about by land conversions for urban development. Results revealed that Mbarara Municipality was experiencing a polynomial type of growth having scored an ‘R squared’ value of ‘1’. The built-up area had increased by 107% between 1984 and 1999 and by 37% between 1999 and 2014 while the overall growth of built-up area between 1984 and 2014 was found out to be 182%. This variation in growth is attributed to the introduction of environmental controls and policies that largely checked the rate of growth between 1999 and 2014. This growth has affected the size of the area covered by other land cover types such as grassland which was seen to greatly fluctuate over the years. The characteristics of urban sprawl in Mbarara Municipality typically depict strip, cluster and leapfrog sprawl. When placed on the OECD sprawl index, Mbarara Municipality was found to be sprawling at a rate of 7.7 between 1984 and 1999 and -7.6 between 1999 and 2014. The overall sprawl rate between 1984 and 2014 was -4.3. This rate has had many implications on environmental planning in Mbarara Municipality through encroachment on existing urban forests. The study suggests that smart growth strategies, upholding zoning practices and the enactment of by-laws to check illegal land conversions are important to check sprawl.