A Case Study on Flood Hazard Potential in the Jaffna District of Sri Lanka
Abstract
The frequent occurrences of natural hazards has been a major challenge to SriLanka. Their effects are felt in the Jaffna district too. For the post war developmentinitiatives in the Jaffna district the assessment of flood hazard potential is vital. Thereare two types of potentials to flood hazards in Jaffna district such as seasonal andspatial.
The main objective of this paper is to find the most vulnerable areas and seasonsto flood hazard from the experience in the Jaffna district. Data was collected fromvarious primary and secondary sources for this study. Monthly rainfall data wascollected from the Department of Meteorology, Colombo for the period from 1960-2011to study the district flood scenario. The data related to recent flood impacts wascollected from the District Disaster Management Unit, Kachcheri, Jaffna and otherprimary data was collected from 120 informants in the flood affected coastal zone byusing stratified random sampling methods.
There are significant spatial and seasonal vitiations observed in the pattern ofrainfall in Jaffna. The variability of flood hazard impact is determined by patterns ofrainfall and elevation of a place. The analysis revealed that the 26% of the low lyingareas in the district has been experiencing severe flooding during the year 2010 and2011. Though the average district rain fall is 1230mm (1950-2011), about 90% ofrainfall generally receives during the period of second Inter Monsoon Season (SIM) andNorth East Monsoon (NEM) Seasons, particularly the peak rainfall was noticed duringthe 48th standard week. Daily rainfall data analysis also revealed that the threeconsecutive days of rainfall was exceeded as 450 mm. Generally the areas around theJaffna and Thondaimanaru lagoons, catchment areas of Valukkaiyaru, Mirusuvil andlow-lying area‟s elevation is less than one meter from the mean sea level where theregions are more vulnerable to flood. These flood prone areas could be carefullymanaged when the development initiatives are taking place.
Key words: Flood hazard, Seasonal Rainfall, Vulnerable Region
