Spatio-Temporal Assessment of Drought using Effective Drought Index (EDI) and Standardized Precipitation Index (SPI) During Monsoon Months in Cuttack District, Odisha, India

Various parts of the World is experiencing frequent droughts due to climatic uncertainties. Drought is the most difficult and least understood natural hazard which can occur virtually in all types of climatic regions. Therefore, improved scientific analysis for forecasting, monitoring and management of drought is required. Effective drought index (EDI) and Standardized Precipitation Index (SPI) is used for drought analysis in this study, as both indices gained popularity as important drought indicators in recent years across space and time. Therefore, EDI 3 Aug (June, July and August), SPI 3 Aug, EDI 3 Sep (July, August and September) and SPI 3 Sep are estimated by utilizing the monthly rainfall data for 30 (1988-2017) years in thirteen blocks of Cuttack District, Odisha, India for characterising drought during monsoon months. The analysis inferred that, highest number of total drought (moderate+severe+extreme) events occurred in Narasighpur block based on EDI 3 Aug and Tangi-Choudwar and Tigiria blocks based on both SPI 3 Aug. Similarly, maximum number of total droughts experienced by Salepur block based on EDI 3 Sep and Cuttack Sadar, Nischintakoili and Tangi-Choudwar blocks as per SPI 3 Sep. Drought maps prepared for the years in decades (1995, 2005 and 2015) to study the variation of drought spatially as well as temporally during monsoon months based on the computed value of drought using EDI and SPI. In the year 1995, no drought events are observed from the drought map based on the drought value of EDI and SPI. Two rainfall threshold values were also estimated for agricultural drought during monsoon months in this study. The threshold limit for agricultural drought varied from 553.9 to 706.3, 516.2 to 722.8, 614.1 to 687.4 and 586.0 to 702.0 mm based on EDI 3 Aug, SPI 3 Aug, EDI 3 Sep and SPI 3 Sep value respectively. This drought analysis will be helpful for implementing various strategies of water management and crop planning for different blocks of Cutttack District.