Analysis of urban expansion and land use/land cover changes using geospatial techniques: a case of Addis Ababa City, Ethiopia

Urban expansion on agricultural land is driven by rapid population growth and is seen as a critical problem in Sub-Saharan African countries. This study was attempted to analyze the dynamics of urban expansion and land use land cover (LULC) changes using geospatial techniques in Addis Ababa City. In the present study, rate and extent of built-up area as well as changes of LULC types were derived from multispectral band of Landsat 5 TM (1990), Landsat 7 ETM + (2003), and Landsat 8 OLI/TIRS (2020), respectively. The expansion of built-up area in the periphery of the city was generated by using supervised classification method with maximum likelihood algorithm from 1990 to2020. The result of the study shows that built-up area was the most dominated LULC types in the study area from 1990 to 2020. Consequently, built-up area was increased by the rate of 2.77km2/year in the past three decades whereas agriculture and grassland were decreased by the 2.68 km2/year and 1.78 km2/year, respectively, over the study period. The results show that the built-up area was increased by an area 83.2km2 while agriculture and grassland were decreased by 80.4km2 and 53.4km2 from 1990 to 2020, respectively. Agriculture and grassland were converted to built-up area by an area of 41.1km2 and 17.3km2, from 1990 to 2020, respectively. This is mainly because of rapid expansion of built-up area and declined of agricultural land and grassland in the periphery of the city. To minimize the rapid expansions of built-up area on agricultural and grassland, the city planners should look other land use types like bare land. Moreover, urban agriculture should be promoted in the periphery of the city. This study can help to improve land use policy and enhance public understanding on the dynamics of LULC change and its implications on sustainable land management around big cities. The use of Geographic Information System (GIS) in urban planning and land use management is essential not optional to minimize the anticipated impacts of urban expansions on agricultural and other LULC classes.