Estimation of Urban Green Cover Changes in Colombo Municipal Area over Ten Years Using Remote Sensing Techniques

Abstract

Colombo is the commercial capital of Sri Lanka, with a high population, buildings, and vehicles. Therefore, it is vital to observe the spatial distribution of vegetation types and changes in the green cover of Colombo city to identify priority areas to improve green cover. This study was carried out to estimate the changes in green cover in Colombo Municipal Area (CMA) and its postal zones over 10 years using remote sensing techniques. The green cover was categorized into trees, shrubs, Playgrounds (PG)/Grasslands, wetlands, rooftops, and Ipomoea cover. Accordingly, total green cover increased up to 26.17% from 22.36% during the period of 2012–2022. During the past decade, except for the PG/Grasslands, all other vegetation types have been reduced. Five of the 15 postal zones in the CMA’s green cover have decreased during the past 10 years, including Colombo 04, 05, 06, 09, and 13. The highest green cover was recorded in Colombo 07, while the lowest green cover was present in Colombo 11. The outcome of the study emphasizes that CMA is moving towards greening and sustainability even with the expansion of built-up areas and urban populations.