Spatio-temporal drought assessment in Tel river basin using Standardized Precipitation Index (SPI) and GIS

The spatial and temporal characteristics of droughts were investigated to provide a framework for agriculture practices, engineering facilities and sustainable water resources management in the Tel river basin which is about 2756 km(2) and lies between 19 degrees 17' and 20 degrees 00'N and 828300 and 82 degrees 59'E in Kalahandi district of Odisha, India. Using the Standardized Precipitation Index (SPI) as an indicator of drought severity for the period from 1965 to 2008, the characteristics of droughts were examined. The multiple-time scaled SPI values were evaluated for May-October months and point-wise indices were interpolated over the whole area using spatial interpolation technique in Arc GIS 9.2, in order to obtain areal extension of the drought severity. The results indicated that a dramatic and widespread drought event was recorded in the year 2002 at most of the stations and drought categories. However, regardless of the drought severity, an extraordinary dryness was experienced in the years 1966, 1972, 1979, 1987 and 2002 in the entire study area. It was observed that 10 years were successively dry during May at Jayapatna station from 1999 to 2008 in the 6-month drought category. The highest SPI value of -3.06 was observed in July 2002 in the Dharamgarh station in the 9-month drought category. The overall outcome of this study demonstrates that severe and extreme droughts were experienced from time to time across the study area leading to unfavourable results on agricultural practices and water resources in the area.