Categorization of Drought During Twentieth Century Using Precipitation in Banaskantha District, Gujarat, India

Abstract

Drought is a natural hazard due to adverse effects in climate change in earth’s environment. Drought assessment is very important to manage water resources in lean period. In the present study, drought years and degree of deficit of annual rainfall are determined by use of Standardized Precipitation Index (SPI-3 to 12 Months), and Percentage Departure from mean (PD) methods. For this study, monthly rainfall data of 102 years (1901–2002), of Banaskantha District, were used. The months of January, February, March, April, May, November, and December have been identified 68, 73, 78, 71, 68, 81, and 79 times as drought months, respectively, in the twentieth century, indicating that these months must be provided with assured Irrigation. From the annual rainfall departure analysis, the drought years have been identified and it is observed that 1901, 1904, 1911,1915,1923,1939,1969,1987, and 2002 are affected by severe drought and 1974 is affected by extreme drought condition. The study also reveals that 6, 15, and 15% of extreme dry years, severe dry years, and moderate dry years occur among drought years considered, which means 36% years are categorized into moderate to extreme drought years out of the total drought years.