Critical determinants on flooding: Perception analysis with reference to Kelani River in Sri Lanka

Flooding receives the priority among the natural disasters in the world. During the past decades, several places in Sri Lanka also were exposed to severe flooding causing massive damages to human lives and properties. A famous place for recurrent flooding in the country finds by the sides of one major river called 'Kelani', and continuous damages reported in Kaduwela Municipal Council limits, where Kelani River flows through. Documentary records show the average annual estimated cost for damages is over USD$50,000/- during the past years in this area. This is an alarming figure to continue and there is inadequate evidence on research, identifying the factors contributing on recurrent flooding. This research aims to analyze the determinants of flooding based on Kelani River, in Kaduwela Municipal Council limits, focusing on both natural and manmade factors. Sixty families through systematic random sampling, were selected representing the most vulnerable areas, to collect data through a structured questionnaire on ten variables and indepth interviews were conducted with five selected experts. The study followed both quantitative and qualitative analysis respectively, descriptive analysis and qualitative method of Analytic Hierarchy Process method used to identify most influencing factors. The findings emphasized that man-made flood causative factors were the most responsible factors for the flood vulnerability in the area even with one-two day's rain. Most significantly, non-availability of a proper drainage system and violation of rules and regulations are the most acute factors. Findings emphasize the necessity to implement proper measures to minimize the flood risk of the area.