Drought Analysis Based on Standardized Precipitation Index (SPI) and Streamflow Drought Index (SDI) in Chenar Rahdar River Basin, Southern Iran

Abstract

In this research, climatologic and hydrologic droughts, as defined by Standardized Precipitation Index (SPI) and Streamflow Drought Index (SDI), were studied in Chenar Rahdar river basin, southern Iran. The basin has a total area of 178 km 2 , a mean elevation of 1637m above mean sea level, and precipitation and stream flow records over the period of 1974 to 2013. SPI and SDI indices over the basin were analyzed for the 40-year record. Overlapping periods of 3, 6, 9, and 12 months were observed. Results showed that an acceptable correlation exists between SPI, as a climatological index, and SDI, as a hydrologic drought index. Analyses revealed that the basin suffered from a range of moderate to extreme droughts during the study period. From the results, one may conclude that both SPI and SDI indices are well capable of capturing the major droughts in Chenar Rahdar river basin for the past 40 years.