Spatial Dynamics of Slum Expansion and Prediction in East African Cities ^†

As the Earth continues to urbanize rapidly, informal settlements are becoming a defining feature of many developing cities. This study examined the growth of slums in Kibera (Kenya), Katanga (Uganda), and Bannyahe (Rwanda) using multi-temporal Landsat imagery from 2000 to 2024. A pixel-based supervised classification was applied to map land use changes, and linear regression models were used to predict slum expansion through 2030. The findings reveal that uncontrolled rapid urbanization in East African cities has significantly contributed to slum proliferation. Specifically, Kibera experienced a slight decline in built-up area from 96.2% in 2018 to 94.3% in 2024. Katanga saw an increase in built-up coverage from 64.5% (0.17 km²) in 2000 to 95.0% (0.27 km²) in 2024. Bannyahe, which had only 4.2% (0.08 km²) built-up land in 2000, expanded dramatically to 67.1% (1.22 km²) by 2021, before a decline in 2024 by 41.8% (to 0.76 km²), accompanied by an increase in bare land from 9.7% (0.18 km²) to 20.6% (0.37 km²) due to relocation and upgrading programs. Classification accuracy ranged from 75% to 99%, with Kappa coefficients between 0.68 and 0.99. Predictive modeling indicates near-total densification in Kibera and substantial growth in Katanga by 2030. The Katanga slum is projected to be predominantly urban, with a built-up area reaching 93.18% (1.743 km²), while Kibera model projections suggest a significant increase in built-up land, with minimal green space remaining, resulting in a built-up area of 99.78% (1.866 km²). These findings are very important for urban planners and policymakers aiming to manage informal settlement growth in alignment with UN Sustainable Development Goal 11 and the African Union’s Agenda 2063.