Assessments of Meteorological Drought Indices Using SPI and RDI in Mehsana Region, Gujarat, India

Abstract

AbstractDrought is one of the natural disasters that in comparison with the other disasters is of tremendous importance due to intensity, duration, areal extent, economic damages and long-term effects. The present work focuses on comparisons of meteorological drought indices, i.e., Standardized Precipitation Index (SPI) and Reconnaissance Drought Index (RDI) for Mehsana district for 1901 to 2002 years. The results of this study show that the RDI is more sensitive than the SPI to climatic conditions and so we can’t neglect the role of potential evapotranspiration in drought assessments. From the results and analysis, it is concluded that extreme dry years are 1904, 1911, 1923 and 1987 wherein severe dry years are 1915, 1918, 1948, 1968, 1972, 1974 and 2002. The results also showed that both indices behave in the same manner in various time scales (3, 6, 9 and 12 months), but RDI due to the use of potential evapotranspiration in similar climatic conditions is more sensitive than the SPI. So, it is recommended that the RDI index should be used as the proper drought index in drought monitoring systems for water resources planning and management. The percentage of drought-affected areas was 20% (Moderate dry 9%, Severe dry 7% and Extreme Dry 4%) and Normal conditions 66% which indicates that the Mehsana region is under dry conditions for most of the years in twentieth century.KeywordsStandardized precipitation IndexReconnaissance drought IndexPercentage drought years