Hydrological drought analysis using SDI index in Halilrud basin of Iran

Abstract

Hydrological drought analysis using SDI index in Halilrud basin of Iran <br />Abstract <br />Nowadays, drought is considered as damaging environmental phenomenon which affects natural resources and social communities. Therefore it will be an important issues that magnitude and effects of these phenomena to be considered. To do this we used L-moment method for regional homogeneity testing. The Streamflow Drought Index (SDI) index was used as a hydrologic drought for investigating probability of drought occurrence in Halilud basin as one of important basins in arid and semi arid regions of Iran which annually suffers form drought damages. Results showed that drought magnitude renege is varied form mild to sever form across basin form upstream to downstream. In other hand frequency of drought occurrence is concentrated in southern of basin. Results also showed high correlation between Standardized Precipitation Index (SPI) as a meteorological index with hydrologic index (SDI). <br />Keywords: hydrological drought index, SDI, SPI, Lmoment, Halilrud basin