Spatial Variations of the Flood and Drought in the Northern Region of Sri Lanka

Abstract

There are no any systematic orders in the occurrences of drought and flood hazards in Sri Lanka. Some areas have higher number of disaster occurrences and some other areas have lower numbers. In this situation this study focused the spatial variations of the drought and flood hazards in the Northern Region of Sri Lanka.  Main objective of this study is to identify the spatial patterns of drought and flood hazards in the study area. Monthly, Seasonal and annual climatic data for the stations Akkarayankulam, Ambalapperumalkulam, Iranaimadu, Kanukkerny, Karukkaikulam, Murunkan, Muththaiyankaddu, Nainathivu, Pallavarayankaddu, Pavatkulam, Thirunelveli, Vavunikkulam, and Vavuniya, were collected for the period from 1972 to 2012. Primary data for this study were collected using interviews and discussions and direct observations. Also varius sources of secondary data were used to carry out this study. Standardized Precipitation Index (SPI) has been used to identify the drought and flood hazards in every station for the period from 1972 to 2012. Krigging method of Arc GIS 9.2 version was used to identify the spatial variations of the drought and flood hazards.  During the South West Monsoon Season (SWMS) 03 severe drought in Vavunikkulam station and 09 in Akkarayankulam, 08 in Murungan, and 08 in Pavatkulam were identified. During the First Inter Monsoon Season (FIMS), extreme floods were experienced in several areas. Three in Iranaimadu, 03 in Thirunelveli, 03 in Pallavarayankaddu and 03 in Nainathivu station were identified in the Northern region using SPI method. During the Second Inter Monsoon Season (SIMS), 02 extreme floods in Thirunelveli, 02 in Vavuniya, and 03 in Murungan, and 02 in Akkarayankulam station and 07 severe droughts in Nainathivu and 05 in Vavuniya were also identified. During the North East Monsoon Season(NEMS), 03 extreme floods in Akkarayankulam, 03 in Ambalapperumalkulam and 03 severe floods, 03 extreme floods in Pallavaraykaddu, 03 severe floods in Muththaiyankaddu, 04 severe floods in Vavunikkulam station and 03 severe floods in Vavuniya were identified in the Northern region of Sri Lanka.

Spatially some areas have been affected many times by flood and drought in the Northern Region of Sri Lanka. Comparatively, Eastern Parts of the study have more flood hazards and more number of droughts has occurred in the Western part of the study. Also 70% of the people expressed above thing. Also frequencies of the flood occurrences gradually decrease in the direction from the east to the west and similarly drought occurrences gradually decrease from the west to the east.

Key Words: Drought, Flood, Seasons, Spatial Variations and Northern Region