Spatiotemporal Analysis and Modeling of Urban Growth Using SLEUTH Model: A Case of Assosa City

Abstract

Urbanization is a global trend with significant environmental effects, urging a clear policy at all levels. Analyzing the dynamics of urban growth on both spatial and temporal scales, as well as future potential growth, has been recognized as a critical step in understanding the consequences of urbanization and developing long-term planning strategies. In this study, Asossa City, one of the rapidly growing regional cities in Ethiopia, is considered to analyze its spatiotemporal growth from 1990 to 2021 and to predict its potential future expansion in the years 2030, 2040, and 2050 under different growth scenarios. Through supervised image classification using the support vector machine algorithm, LULC maps of the study area in 1990, 2000, 2010, and 2021 were prepared, and the spatiotemporal changes of LULC were investigated. Five selected spatial metrics (number of patches, patch density, edge density, largest patch index, and area weighted mean patch fractal dimension) were used to examine the dynamics of landscape structure in the study area over time. Urban development typologies were also analyzed using the spatial link between pre-growth and newly built components. By modeling the growth of the study area using the SLEUTH model, the future potential growth extent of the city was forecasted for the years 2030, 2040, and 2050, under three growth scenarios: business as usual, planned growth, and environment-protecting. The results show that the built-up area has undergone about 14% expansion annually in the past 31 years, indicating rapid urban growth. The urban area of the city experienced a fragmented urban growth process, particularly, at the fringe, while the core of the city underwent relatively compact growth by infilling open spaces and through edge expansion over time. Moreover, the prediction results of business as usual scenario indicates that 1801.7ha, 2493.33ha and 3267.4ha of land will be covered by built-up area in 2030, 2040 and 2050 respectively. Similar to this, the predicted result of planed growth scenario indicates that the built up area will reach 1723.9ha, 2207.8ha and 2885.7ha in 2030, 2040 and 2050. In environment-protecting scenario Built-up area will be 1718 ha in 2030 and 2179.9ha in 2040. In 2050 it was predicted as 2778.6ha. This study would assist planners and prospective stakeholders in planning a new heading before adverse effects become unavoidable. The formulation of urban planning policy should also work to strike a balance between socioeconomic requirements and the sustainable use of finite resources.