Assessment of climate extremes based on SPI in WL1 agroecological zone - a case study from Kuruwita, Sri Lanka

Abstract

—Drought and flood are the simple most significant climatological hazards in Sri Lanka, which primarily affects agricultural productivity. Proper understanding and investigation of climatic extremes like drought and floods play a key role in planning and management of the household, municipal, agricultural and industrial activities even with varied water availability. Therefore, the present the study aimed to assess onset, severity, and occurrence of drought and wet episodes (months) in Kuruwita region, which belongs to the Low Country Wet Zone Agro-ecological region using the Standardized Precipitation Index (SPI) at various time scales. SPI analyzed at 12 months’ time interval revealed that out of 45 years of the study period (1961-2005), there were only four (1976, 1980-1981 and 1996) and six (1985-1986, 1988-1989, 2003-2004) drought and wet hydrological years, respectively. Further, the hydrological years 1981 and 2004 were identified as more affected years by drought and wet events, respectively, with a relatively higher occurrence of climate extremes depicted by SPI, than normal conditions. The South-West monsoon (SWM) was found to be more prone to extreme climatic conditions, leading the Yala cropping season to become more abnormal with the occurrence of more drought and wet months in Kuruwita. Therefore, the study suggests that the implementation of proper mitigative measures like installation of rainwater harvesting systems, reuse or recycling of rainwater, cultivation of stress-tolerant crop varieties, adaption of different cropping systems would be beneficial to minimize such adverse effects and for sustainable development in Kuruwita area.