Dynamics of Urban Sprawl in Dar es Salaam: A Three-Decade Analysis Using Remote Sensing and Landscape Metrics

Abstract

Urban sprawl presents critical challenges to sustainable urbanization in rapidly growing cities. This study integrates remote sensing and landscape metrics to analyze urban sprawl over three decades (1995–2024), using multi-temporal Landsat imagery and advanced classification techniques to quantify urban growth patterns and spatial dynamics through metrics such as Percentage of Landscape (PLAND), Number of Patches (NP), Patch Density (PD), and Total Edges (TE). The findings reveal an unprecedented increase in built-up areas, expanding from 73 km² (4.41%) in 1995 to 131 km² (7.92%) in 2009 and further to 409 km² (24.73%) by 2024, marking a 20.31 percentage rise over the study period and underscoring the rapid urbanization of Dar es Salaam. Landscape metrics highlight increasing fragmentation, with NP rising from 5,432 in 1995 to 26,368 in 2024 and TE surging from 2,464,006 to 15,211,345, reflecting intensified patchiness and boundary complexity. Additionally, directional expansion patterns and reduced landscape connectivity, as evidenced by the declining Aggregation Index (AI) and greater landscape diversity and evenness, point to significant ecological and infrastructural implications. These results provide a comprehensive understanding of urban sprawl and emphasize the need for sustainable urban development strategies that balance growth with environmental conservation and efficient land use planning, ensuring the long-term resilience of rapidly urbanizing cities like Dar es Salaam.