IMPACTS OF LAND USE CHANGE FOR STORM WATER FLOOD IN SUB URBAN CONDITIONS; A CASE STUDY IN COLOMBO (original) (raw)

All living beings modify their environment. Humans are no exception; they have modified lands to obtain food and other needs for thousands of years. Present rates, extents and intensities of Land Use Change (LUC) are far greater, resulting driving unprecedented changes in ecosystems and environmental processes at local, regional and global scales. Aftermath of this contemporary issue the natural disasters such as Floods, Drought, Cyclones, Landslides etc. becoming a frequent phenomenon. Storm water floods are more recurrent hazardous events for urban regions in Sri Lanka. Colombo is the preeminent city where people, resources and infrastructure are concentrated. After decentralizing Colombo; suburban residents also suffered not only by urbanization pressure but also the consequences of mindless urbanization. Hence, this study is focused on analysing the effect of land use change for the storm water flooding in Colombo sub urban conditions. Numbers of studies have been carried out in this regard; however, severe effects that people are doing to natural environment have not been fully addressed. This study incorporates with the World view_2 panchromatic, multispectral and stereo images. Land use change was identified from the land use maps generated by classified images and where the Support Vector Machine became the most appropriate classification technique for a suburban composition with resulting 80% classification accuracy and more than 0.8 Kappa Coefficient. Marsh lands which identified as major land use type for the flood scenario of the area and significant marsh lands had identified for the analysis. Analysis were carried out regarding mutation of those land cover (2007, 2000, 2004, 1983) with the water level data and meteorological components for the identification of effect of land use change for this dilemma.