Geospatial Analysis of Urban Green Space Dynamics in Matara City: Implications for Sustainable Urban Planning

Green spaces have seen major changes as a result of the fast urbanization and population expansion. Accessible urban green spaces are essential, particularly in view of the Urban Heat Island (UHI) effect and the growing significance of ecological resilience in metropolitan areas. This study investigates the changes in green spaces within the Matara MC from the years 2003 to 2023, occurred by the pressures of rapid urban growth. The primary objectives of the research were to: (a) identify and quantify the extent of green spaces in Matara MC over the past 20 years, (b) analyze and compare the changes in green spaces from 2003 to 2023, and (c) calculate the changes in green space per capita based on the recommended standards. The study utilized geospatial techniques, along with the Normalized Difference Vegetation Index (NDVI), to assess urban green space dynamics. Accuracy of the results was evaluated using a confusion matrix, with an overall accuracy of above 75%. In 2003, the green space cover had an extent of 14.288 km², accounting for 73% of the total area. However by 2023, it had decreased to 9.096 km², or 48% as a percentage of the area. The central city experienced a considerable loss in green space, while boundary areas also saw reductions. The overall per capita green space decreased from 139 m² in 2003 to 120 m² in 2023, with several Grama Niladari Divisions (GNDs) now falling below the World Health Organization’s (WHO) recommended value as 9.5 m² per person. These findings emphasize the urgent need for strategic urban planning to mitigate further green space loss. To address these challenges, recommendations include the implementation of sustainable urban planning practices, the restoration of degraded lands, and active community involvement in green space conservation. These steps will promote future urban growth in the Matara MC while ensuring the protection of natural resources.