Statistical Modeling of Extreme Drought Occurrence in Bellary District of Eastern Karnataka

Abstract

Drought is a natural hazard which may temporarily affect any region in the world by several means. In the present study frequency analysis of meteorological drought in the Bellary region of Karnataka has been investigated for 52 years (1961–2012) using the Standardized Precipitation Index (SPI) at short (SPI-1 and SPI- 3), medium (SPI-6) and long (SPI-12) time scales. This method aims to provide a concise overall picture of drought, regardless of the actual probability distribution of the observed cumulative amount of rainfall for a given time scale. By applying the SPI methodology, results indicated that drought randomly affected a region and several drought events occurred during the period analyzed. The generalized extreme value (GEV) distribution was fitted to data from the location to describe the extremes of rainfall and to predict its future behavior. Minimum assured drought at 50 % probability level was observed to be a better representative of long-term average of drought (minimum SPI) in the region as depicted by the GEV distribution. The return period analysis indicate that the region experiences extreme drought (SPI\-2) every ten or less years for all time scales, whereas moderate to severe drought occurs every alternate year. There is thus a necessity to prepare contingency plans for the region and focus on the cultivation of those crops with a capacity of withstanding droughts of moderate intensity which will be used as a guide for water resource management in the region during droughts.