Assessing the impact of southern expressway on land fragmentation: with special reference to western province

Abstract

Assessing and quantifying land fragmentation enables transport planners to make informed decisions on optimizing infrastructure; routes; land uses and consider deeply on environment and public accessibility. The study aims to assess the impact of the Southern Expressway (SE) which is one of the mega-scale transport development projects in Sri Lanka, on land fragmentation (LF) near interchanges in the Western province. The study analyzed the land fragmentation at 5km buffer zone of Kottawa and Gelanigama interchanges between 2001 and 2021, utilizing ArcGIS 10.8, Landsat ETM+ images and Fragstat 4.2. Results revealed that, Number of patches (NP) and Patch density (PD) across all land covers, except built-up lands of Kottawa significantly increased from 2001 to 2021 indicating the SE has impacted LF over the area. Area mean (Area MN) of built-up lands of Kottawa significantly expanded (0.5548 ha in 2001, 3.1722 ha in 2021). The largest patch index (LPI) of cultivated lands in Gelanigama was 7.5716% (2001) and drastically dropped to 0.7159% (2021) indicating the patch sizes becoming smaller. The identified changes in LF and patch characteristics have several implications for future transport development. Future transport development requires sustainable and integrated planning considering environmental, social, and economic factors to create a resilient, livable environment for the area’s inhabitants.