Impacts of uncontrolled urban expansion on urban decay using remote sensing and GIS technique: the case of ambo town, Ethiopia

Abstract

Urban blight is a complicated issue that can have a negative effect on urban residents' quality of life. The use of remote sensing and GIS techniques can provide valuable insights into the extent and severity of urban blight. Urban poor populations in Ambo Town's inner cities lead to social and economic problems. Thus, this study aims to assess the existing condition of urban blight and map the spatio-temporal pattern of urban decay in Ambo using multi-date remote sensing data. The change detection of multiple Landsat images was conducted to map and analyses the extent and rate of urban growth in Ambo Town between 1992 and 2022. The study was conducted based on qualitative and quantitative approaches using spatial analysis of remote sensing and GIS techniques and survey methods. The primary data sources were collected using questionnaires and observations to identify the perceptions of office employees and the town's community on the factors that contribute to urban blight in the inner part of Ambo town. The secondary data sources were collected using satellite images. The results of the study showed that grassland and agricultural land covered 41.45% and 33.94% of the total area at the beginning of the study, respectively. By contrast, the proportion of the urban class was 2.93% in 1992 and rose to just over 16.65% in 2022. Agriculture decreased by 59.31% in the past 30 years, with grassland contributing the most net change in a built-up area (765 ha), followed by agriculture land (612 ha) and forest area (34 ha). That level of urban blight by the physical composite blight index town was 0.78; the socioeconomic and political composite blight scores were 0.66 and 0.72, respectively. The composite blight index, which takes into account physical, sociological, economic, and political variables, is 0.72 overall. The Composite Blight Index appears to be a measure of the degree of blight in Ambo town, with a value of 0.72 signifying a moderate amount of blight. Urban growth is associated with population growth, economic development, and the expansion of infrastructure and services, while urban blight is associated with economic decline, population loss. Therefore, this information can be used to inform policy decisions related to urban renewal, rehabilitation, and redevelopment, with the goal of creating more sustainable and livable urban environments