Trends of floods in Sri Lanka

Shammi De Silva, Shriyangi Aluwihare, Janaki Chandimala, Rohan Jayasooriya, Rasadari Undugodage

Tuesday 30 june 2015

17:00 - 17:15h at South America (level 0)

Themes: (T) Flood risk management and adaptation, (ST) Flood risk assessment

Parallel session: 7J. Floodrisk - Assessment

This study presents results of an analysis carried out in obtaining trends of floods in Sri Lanka based on the available records of flood events during last 20 years. Ten major river basins which are vulnerable to floods encompassing a significant portion of Sri Lanka have been selected for the analysis of flood disaster trends. Loss of life, families affected, and houses damaged and destroyed due to extreme flood events were taken as tools to determine the magnitude of floods. Frequency of occurrence of floods was determined by the number of flood events occurred in the respective basins for the last 20 years. At basin level, the results indicate an increasing trend of flood disasters. But in some basins a significant amount of unexplained variance remains; mainly due to the minor mitigation strategies practised in the respective basins. At the national level, an increasing trend both in occurrence and magnitude of floods in Sri Lanka can be observed when loss and damage data in a nation – wide basis is reviewed. However a considerable amount of variance can be observed in the results due to the variability of factors such as climatic changes, un-planned development, environmental degradation and human interventions. Keywords: Damages, Flood, Occurrence, Sri Lanka, Trends,