Assessment of Green Space Requirement and Site Analysis in Colombo, Sri Lanka - A Remote Sensing and GIS Approach

Green space distribution plays a vital role in urban planning since they contribute significantly in enhancing environmental quality of metropolitan areas by improving air quality, urban health, conserving biodiversity, reducing noise, etc. Migration of rural population into urban areas and widespread industrialization lead to the rapid growth of urban population, consequently expanding urban sprawls. Removal of vegetation cover can be identified as one of the most adverse effects of urbanization. Proper distributi on of green spaces in urban environments is therefore a necessity for the sustainable development and healthy living. Hence, it is essential to identify the green space requirement quantitatively and spatially. In this endeavour, integration of remote sensing and GIS techniques can provide a time and cost effective methodology.Colombo city of Sri Lanka has been identified as one of the most polluted cities in South Asian region. Rapid urbanization and the population growth are the main causes for the degradation of environmental quality in Colombo. Unplanned constructions and settlements in Colombo have contributed to significant reduction of green spaces. Therefore, special consideration has to be made for the proper distribution of green spaces in future development and planning projects in Colombo. In this study, available green spaces in Colombo are extracted through NDVI method using THEOS satellite imagery. Subsequently, green spaces required to be created are calculated with respect to WHO standards of green spaces per capita for healthy living (9.5 m2/ person) and a methodology is developed to spatially define appropriate areas to establish them.